play (right) into the hands of (one)

play (right) into the hands of (one)

To unwittingly do exactly what one wants or needs in order for one's plans or schemes to succeed. Don't waste your time investigating her husband! You're playing into the hands of the real killer! These violent, hate-filled demonstrations are playing right into the hands of the groups we're protesting against.
See also: hand, of, play
Farlex Dictionary of Idioms.

play into the hands of

Act so as to give an advantage to an opponent, as in The senator played right into the hands of her opponents when she backed that unpopular amendment to the tax bill . [c. 1700]
See also: hand, of, play
The American Heritage® Dictionary of Idioms by Christine Ammer.
See also:
  • play (right) into (one's) hands
  • play into hands
  • play into somebody's hands
  • play into someone's hands
  • play into the hands of
  • (one's) old man
  • at (one's) doorstep
  • at doorstep
  • (from) top to toe
  • at expense